Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#1 2007-10-14 11:21:20

simone
Member
Registered: 2007-10-05
Posts: 19

algebra help

Hi, could you please help me solve this question? Thank you!faint



If x and y are positive, which of the following must be greater than  1/sqrt(x+y)   ?

1)  (sqrt(x+y))/(2x)

2)  (sqrt(x)+sqrt(y))/(x+y)

2)  (sqrt(x)-sqrt(y))/(x+y)

Offline

#2 2007-10-14 13:01:39

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: algebra help

So the middle one is true. The others are false; you can easily find counterexamples.

Last edited by JaneFairfax (2007-10-14 13:11:35)

Offline

#3 2007-10-14 20:44:29

simone
Member
Registered: 2007-10-05
Posts: 19

Re: algebra help

thank you so much Jane.kiss

Last edited by simone (2007-10-14 20:44:49)

Offline

Board footer

Powered by FluxBB